How can I get a boot script to load automatically?

You will need to store the script in the serial EEPROM. To have LogicLoader automatically start this script, "name" it "LOLO" or "VOLO". If the first four bytes in the serial EEPROM are "LOLO" or "VOLO", the LogicLoader software will grab everything after it and up to a newline and treat it like a command typed at the "LOSH>" prompt. For more information, and an example, please see the LogicLoader User Manual.